package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.conditions.query.QueryChainWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.apache.tomcat.util.buf.StringUtils;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.geo.Metric;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.data.redis.domain.geo.Metrics;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.SHOP_GEO_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {


    @Resource
    private  StringRedisTemplate stringRedisTemplate;

    @Resource
    private  CacheClient cacheClient;



    private static final ExecutorService CACHE_REBUILD_EXECUTOR= Executors.newFixedThreadPool(10);
    @Override
    public Result queryById(Long id) {
//        工具类解决缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        互斥锁解决缓存击穿
//        Shop shop = queryWithMutex(id);
//        逻辑过期解决缓存击穿
//        Shop shop = cacheClient.queryWithLogicalExpire(RedisConstants.CACHE_SHOP_KEY,id,Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        if (shop==null){
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }

    public Shop queryWithMutex(Long id)  {

        String key= RedisConstants.CACHE_SHOP_KEY +id;
//        1.从redis查询店铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);

//        2、判断是否存在
        if (StrUtil.isNotBlank(shopJson)){
//        3、存在直接返回
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return shop;
        }
        if (shopJson!=null){
            return null;
        }
//        4、不存在，根据id查询数据库
//        缓存重建，获取互斥锁，判断是否获取成功
        String lockKey=RedisConstants.LOCK_SHOP_KEY+id;
        Shop shop=null;
        try {
        if (!tryLock(lockKey)){
                Thread.sleep(50);
            return queryWithMutex(id);
        }
        shop=getById(id);
        if (shop==null){
//        5、不存在，抛出错误
            stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL,TimeUnit.MINUTES);
            return null;
        }
//        6、存在，写入redis
        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL,TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
//        7、释放互斥锁
            unLock(lockKey);
        }
        return shop;
    }
    public Shop queryWithLogicalExpire(Long id){
        String key= RedisConstants.CACHE_SHOP_KEY +id;
//        1.从redis查询店铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        2、判断是否存在
        if (StrUtil.isBlank(shopJson)){
//        3、不存在直接返回
            return null;
        }
//        4、命中需要json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        Shop shop=JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();

//        5、判断是否过期，未过期就直接返回店铺信息，过期就缓存重建
        if (expireTime.isAfter(LocalDateTime.now())){
            return shop;
        }

//        6、缓存重建，获取互斥锁，判断是否获取成功
        String lockKey=RedisConstants.LOCK_SHOP_KEY+id;
        if (tryLock(lockKey)) {
//        成功就开启新独立线程实现缓存重建
//            使用线程池，异步执行，防止阻塞主线程
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    saveShop2Redis(id,20L);
                    unLock(lockKey);
                }catch (Exception e){
                    throw new RuntimeException(e);
                }
                finally {
                    unLock(lockKey);
                }
            });
        }
//        失败就直接返回过期信息
        return shop;
    }
    public Shop queryWithPassThrough(Long id){
                    String key= RedisConstants.CACHE_SHOP_KEY +id;
//        1.从redis查询店铺缓存
            String shopJson = stringRedisTemplate.opsForValue().get(key);

//        2、判断是否存在
            if (StrUtil.isNotBlank(shopJson)){
//        3、存在直接返回
                Shop shop = JSONUtil.toBean(shopJson, Shop.class);
                return shop;
            }
            if (shopJson!=null){
                return null;
            }
//        4、不存在，根据id查询数据库

            Shop shop=getById(id);
            if (shop==null){
//        5、不存在，抛出错误
                stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL,TimeUnit.MINUTES);
                return null;
            }
//        6、存在，写入redis
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL,TimeUnit.MINUTES);
            return shop;
    }

    public void saveShop2Redis(Long id , Long expireSeconds) throws InterruptedException {
//        1、查询店铺数据
        Shop shop = getById(id);
        Thread.sleep(200);
//        2、封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
//        3、写入redis
        stringRedisTemplate.opsForValue().set(RedisConstants.CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id=shop.getId();
        if (id==null){
            return  Result.fail("店铺ID为空");
        }
//        1，更新数据库
        updateById(shop);
//        2，删除缓存
        String key= RedisConstants.CACHE_SHOP_KEY +id;
        stringRedisTemplate.delete(key);

        return Result.ok();
    }

    @Override
    public Result queryShopOfType(Integer typeId, Integer current, Double x, Double y) {
//        判断是否需要根据坐标查询
        if (x==null||y==null){
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
//        计算分页参数
        int from = (current-1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current*SystemConstants.DEFAULT_PAGE_SIZE;

//        查询redis，按照距离排序、分页
        String key = SHOP_GEO_KEY+typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(
                key,
                GeoReference.fromCoordinate(x, y),
                new Distance(1000000000.0, Metrics.KILOMETERS),
                RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance()//withDistance()
                        .limit(end)//from 0 to end
        );
//        解析出id
        if (results == null) {
            return Result.ok();
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size()<=from){
            return Result.ok();
        }
        List<Long> ids = new ArrayList<>();
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(geoResult -> {
            String shopIdStr = geoResult.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            Distance distance = geoResult.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
//        if (ids.isEmpty()){
//            return Result.ok();
//        }
//        根据id查询店铺信息
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("order by field(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        return Result.ok(shops);

    }

    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    private  void unLock(String key){
        stringRedisTemplate.delete(key);
    }

}
